In an ideal world, we'd weigh all of our ingredients—it's the only way to guarantee 100% accuracy. But sometimes your kids steal the batteries from your scale to power their gaming habits and you need to dig out the cups and spoons.
No matter how accurate your measuring cups and spoons are, the way you use them can skew the results. The first hurdle is choosing the correct measuring cups for your ingredients. Liquids should always be measured in a graduated glass or plastic measuring cup, while the flat-topped measuring cups that come in set sizes should be used for dry goods.
Measuring Wet Ingredients
Although it seems like dry cups should work for liquid ingredients, in practice it's not very successful. If you fill a dry measure with liquid, you'll see that the water actually rises a bit over the top (sort of like a flat bubble) and if you try to move too far with that cup, you're going to spill some. If you fill it less full, you've got the wrong amount.
When you measure liquid in the graduated glass measuring cup, the liquid will form that same surface bubble. In geek-talk it's called the meniscus, but you don't need to know that. Just remember that to accurately measure wet ingredients, put your eye right down to the counter so that it's level with the measuring line. The meniscus should line up perfectly with that line, like this:
Measuring Dry Ingredients
Dry measures are more tricky. Things like sugar and ball bearings are fairly easy to measure. You get them into your dry cup by whatever means is practical, level the top off with a flat implement (like a knife, ruler, or chopstick) and you're done.
Flour, on the other hand, is more complicated. The problem with flour is that depending on how you get it in the measuring cup, you can fluff it up like a pillow or compress it like brown sugar. That range of super-fluffy to completely compacted can result in a cup of all purpose flour weighing anywhere from 4 to 6 ounces—more than enough to throw your recipe completely out of whack.
At Serious Eats, we favor the dip-and-sweep method: store your flour in a large container, dip the measuring cup directly into the container and scoop the flour up. Then, level then top off with a flat implement. It's the easiest method, and relatively precise compared to more error-prone methods like sifting the flour into the cup or spooning it in. Measuring in this manner yields cups of all-purpose flour that should weigh 5 ounces each.
In other cookbooks or websites (or in some of our older recipes), many cake recipes will tell you to sift the flour directly into the measuring cup. Resulting in only 4 to 4.5 ounces of flour per cup. But be careful—some recipe specify measuring, then sifting, while others ask you to sift, then pour the sifted flour into the cup, and still others ask you to sift directly into the cup. Double-check the instructions before you measure.
Since weight is the most accurate measure, it's good to know what the recipe author thinks a cup of flour weighs, or how that author recommends measuring. That way, your measurements are equal to what the author had in mind. Any good baking book will indicate how much a cup of flour should weigh either in the introduction to the book, in an appendix, or in-line with the recipes. It's a good idea to check for those instructions and make sure that you're using the correct weight conversions. And if the book doesn't have weight conversions? Well, in that case, you should seriously consider looking at a different book!
The volume-to-weight conversion that Serious Eats has standardized for its writers, based on the dip-and-sweep measuring method, is:
- 5.5 ounces per cup for bread flour
- 5 ounces per cup for all purpose flour
- 4 ounces per cup for cake flour
If you use those weights or the dip-and-sweep measuring method, you should get the results the Serious Eats recipe writer intended.